A Solution to Islanding Event Detection Using Superimposed Negative Sequence Components-Based Scheme

Failure of islanding detection techniques leads to improper operation of DGs, risk for working personnel, loss of control over voltage and frequency, uncoordinated protection, poor power quality, etc. Therefore, the islanding event (IE) should be identified, and its detection algorithm should be incorporated according to the standard guidelines. Through this paper, a communication-assisted passive islanding detection technique (IDT) is proposed based on an index, which is the ratio of multiplications of superimposed negative sequence voltages and currents of DG and grid sides. Proposed ID is implemented in the modified IEEE-13 bus system through the micro phasor measurement unit. The calculated index is compared with a set threshold to discriminate between the IEs and non-islanding events (NIEs). The calculation of threshold is not very complex as compared to other schemes. The efficacy of the proposed IDT is tested under various system conditions, such as zero power mismatch (ZPM), wide range of active power mismatch, and reactive power mismatch. DG disconnection and unbalanced load test cases are also performed under ZPM condition. Similarly, different NIEs like capacitor switching, load switching, nonlinear load and different fault cases are verified through the proposed IDT. Real-time implementation of proposed IDT is conducted using opal-RT.